Recent work has demonstrated that light induced free radicals and a variety of fatty acids are capable of altering the physiological function of corneal endothelium. The purpose of this investigation includes the following: 1) Obtain a better understanding of how photosensitization, photooxidation, free radicals, singlet oxygen, and peroxides may alter endothelial cells. 2) Determine if alterations of endothelial cell membrane lipid content and fluidity may be of benefit in protecting endothelial cells from chemical and physical trauma and enhance corneal storage capabilities of tissue culture (MK) Medium. 3) Determine the effect of a variety of compounds on cornea endothelial bicarbonate fluxes and their possible relationship to corneal water movement. Parameters to be studied include corneal swelling rates, sodium and bicarbonate fluxes, non-ionic fluxes and cell ultrastructure.